1. Field of the Invention
The present invention relates to metal shaping, and more particularly to a mill for making transverse deformations or corrugations on a sheet metal.
The term "transverse deformation" as used herein refers to making transversely extending deformed portions or corrugations on uninterruptedly moved sheet metal. The deformed portions are shaped as parallel corrugations surrounded by flat (undeformed) portions which separate the former from each other and from the metal strip periphery.
The mill of the present invention is preferably intended to be used in metallurgy or in a machine-building industry for manufacturing sheet metal panels reinforced with corrugations. Such sheet metal panels are widely used as building structural units or metalcoating for freight containers and the like.
2. Description of the Prior Art
Known in the art is a mill for cold making transverse deformations on a sheet metal (U.S. Pat. No. 3,509,753) comprising a rolling stand with forming rolls having congruent lengthwise arranged forming elements, and a drive stand. Mills of the above type are commonly used for manufacturing thin-gauge sheet metal panels with shallow corrugations deepened thereinto for no more than two or three times the material thickness.
Nowadays, transversely corrugated sheet metal panels find ever increasing application. The field of application for such panels has extended as well, which consequently advances a number of additional requirements. Thus, a requirement has arisen for improving the supporting power of such panels. To meet this requirement, the manufacturers have to use sheet metals either of a higher strength, i.e. of low plasticity, or high plasticity sheet metals of a heavier gauge. In both cases, the supporting power of a sheet metal panel may additionally be improved through an increase of the corrugation depths.
Yet it is well known that high-strength steels are difficult to shape in a cold state because of their poor plasticity. The cold roll shaping of such steels is, therefore, impracticable because they are liable to shattering and cracking in portions being corrugated.
The use of sheet metal of a heavier gauge calls for a considerable increase in the power consumption and, consequently, an increase in the drive power of the rolls of the rolling stand as well as an increase in the overall dimensions of the rolling stand up to a technologically unreal size.
In addition, an increase in the corrugation depths leads to a cross-sectional distortion (twisting) of flat portions in shaped sheet metal panels. This results from sharply differing stresses between portions being corrugated and portions being kept flat.
Also known is a mill for making transversely extending deformations on a sheet metal (USSR Inventor's Certificate No. 513,094) which is intended for manufacturing sheet panels of a high-strength or thickgauge plastic sheet metal, which panels have deep transverse corrugations exceeding in height three times the material thickness. The mill comprises at least one rolling stand with rolls having congruent lengthwise arranged forming elements, at least one drive stand, and means for locally heating the sheet metal at its portions to be transversely corrugated. The locally heating means includes inductors with a cooling system and a mechanism adapted to move the inductors towards the sheet metal and therefrom. The inductor-moving mechanism is made in the form of a continuous belt adapted to transport the inductors positioned thereon at intervals equal to the spacings between the portions to be transversely deformed on the sheet metal. The continuous belt drive roller is kinematically (operatively) connected with one of the rolls of the rolling stand. The inductor cooling system includes a drum having two chambers one of which communicates with a coolant source and the other communicates with a coolant discharge means. The drum chambers also communicate with hoses connected to the inductors.
When the sheet metal is fed towards the forming rolls of the rolling stand, each of the inductors on the continuous belt at the side thereof facing the sheet metal accompanies an appropriate portion of the sheet metal and heats the same up to a pre-assigned temperature. As the heated metal portion is fed into the clearance between the rolls, the appropriate inductor is transferred to the other side of the continuous belt. As the inductor is being transferred, the drum is turned to prevent the hoses connected thereto from being snarled or twisted.
Despite the fact that the mill described above is intended to make transverse deformations on a high-strength and thick-gauge plate metal, the employment thereof involves some difficulties. These difficulties consist in that in re-adjusting the mill to the metal panels with different spacings between adjacent corrugations, it is required to remove therefrom or to add thereto some inductors, or to change the length of the continuous belt by removing therefrom or adding thereto some links. Besides, since the inductors are mounted on a flexible element, i.e. a continuous belt, it is difficult to maintain a constant optimum clearance between the sheet metal and the inductors when the metal is being heated. This involves a loss of power, a low heating effect and, finally a low quality of the products manufactured by the mill.
To enable the continuous belt to move in synchronism with the drum, it is necessary to use complicated additional means.
One of the disadvantages of the known mill is that, when it is in operation, only half of the heating inductors are operated. That is, when one part of the inductors is moved in synchronism with and facing the sheet metal to provide local heating thereof, the other part is moved in the opposite direction (being on the other side of the continuous belt) and thus takes no part in the heating process. Therefore, in addition to an ineffective use of practically half the inductors, the means of the above type for locally heating the sheet metal, in case the spacings between the adjacent sections are to be deformed are great, leads to a considerable increase in the spacing between rolling stands and eventually to an increase in the total mill length.
The object of the invention is to overcome the above-mentioned disadvantages.
It is an object of the invention to provide a mill for making transverse deformations on a sheet metal which makes it possible to simplify the mill construction and reduce the mill length.
A further object of the invention is to provide a mill for making transverse deformations on the sheet metal, comprising such means for locally heating the sheet metal which enables the mill to be move effective and reliable.
Yet a further object of the invention is to provide a mill for making transverse deformations on the sheet metal, comprising such means for locally heating the sheet metal which makes it possible to decrease the mill power consumption.